The primary goal of this study is the increase in knowledge of treatment methods for patients with pediatric malignancies. The specific aims are the collaboration with other investigators in the Cancer and Leukemia Group B with entry of patients on cooperative protocols so that information can be obtained on a number of patients too small to be obtained at any individual institution in patients with these rare pediatric tumors. Patients will be studied in a scientific fashion. The majority of studies will be prospective randomized trials of conventional therapy vs. some innovative aspect of treatment. In some tumors, where no adequate conventional therapy exists, historical controls may be employed. This project represents a collaborative effort between the departments of oncology, pediatrics, surgery and radio therapy. The principal studies will involve the evaluation of new modalities of therapy and new drugs in cancer patients. Excellent patient care and detailed record keeping will be required.